/*********************************************************************************
 *                                                                               *
 * The MIT License (MIT)                                                         *
 *                                                                               *
 * Copyright (c) 2015-2020 aoju.org Greg Messner and other contributors.         *
 *                                                                               *
 * Permission is hereby granted, free of charge, to any person obtaining a copy  *
 * of this software and associated documentation files (the "Software"), to deal *
 * in the Software without restriction, including without limitation the rights  *
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell     *
 * copies of the Software, and to permit persons to whom the Software is         *
 * furnished to do so, subject to the following conditions:                      *
 *                                                                               *
 * The above copyright notice and this permission notice shall be included in    *
 * all copies or substantial portions of the Software.                           *
 *                                                                               *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR    *
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,      *
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE   *
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER        *
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, *
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN     *
 * THE SOFTWARE.                                                                 *
 ********************************************************************************/
package org.aoju.bus.gitlab;

import java.util.Collections;
import java.util.Iterator;
import java.util.Spliterator;
import java.util.function.Consumer;

/**
 * @author Kimi Liu
 * @version 6.0.9
 * @since JDK 1.8+
 */
class PagerSpliterator<T> implements Spliterator<T> {

    private Pager<T> pager;

    private Iterator<T> elements;

    PagerSpliterator(Pager<T> pager) {
        this.pager = pager;
        if (pager.hasNext()) {
            elements = this.pager.next().iterator();
        } else {
            elements = Collections.emptyIterator();
        }
    }

    @Override
    public boolean tryAdvance(Consumer<? super T> action) {
        if (action == null) {
            throw new NullPointerException("Action is null");
        }
        if (elements.hasNext()) {
            action.accept(elements.next());
            return true;
        } else if (pager.hasNext()) {
            elements = pager.next().iterator();
            action.accept(elements.next());
            return true;
        }
        return false;
    }

    @Override
    public Spliterator<T> trySplit() {
        return null;
    }

    @Override
    public long estimateSize() {
        return pager.getTotalItems();
    }

    @Override
    public int characteristics() {
        return SIZED | NONNULL;
    }

}
